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Missouri University of Science and Technology

1998

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Frontal Chromatography Of Proteins: The Effect On Column Performance Of The Restricted Diffusion Of Molecules In Porous Chromatographic Adsorbents, Athanasios I. Liapis, H. Sadikoglu, Orrin K. Crosser Dec 1998

Frontal Chromatography Of Proteins: The Effect On Column Performance Of The Restricted Diffusion Of Molecules In Porous Chromatographic Adsorbents, Athanasios I. Liapis, H. Sadikoglu, Orrin K. Crosser

Chemical and Biochemical Engineering Faculty Research & Creative Works

A theoretical formulation is presented that can be used to describe the dynamic behavior of frontal chromatography of proteins in columns packed with adsorbent particles in which restricted pore diffusion of the adsorbate molecules occurs. The results of this work clearly indicate that the time for breakthrough and the effective utilization of the adsorptive capacity of the chromatographic particles increase as (a) the size of the adsorbate and/or ligand (active site) molecule decreases, (b) the pore connectivity, n(T), of the porous network of the adsorbent particles increases, and (c) the column length, L, increases. Copyright (C) 1998 Elsevier Science B.V.

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Effect Of Temperature On Retention Of Enantiomers Of Β-Methyl Amino Acids On A Teicoplanin Chiral Stationary Phase, Antal Péter, Gabriella Török, Daniel W. Armstrong, Géza Tóth, Dirk Tourwé Dec 1998

Effect Of Temperature On Retention Of Enantiomers Of Β-Methyl Amino Acids On A Teicoplanin Chiral Stationary Phase, Antal Péter, Gabriella Török, Daniel W. Armstrong, Géza Tóth, Dirk Tourwé

Chemistry Faculty Research & Creative Works

The isocratic retention of enantiomers of β-methyl amino acids (β-methyltyrosine, β-methylphenylalanine, β-methyltryptophan and β-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) was studied on a teicoplanin-containing chiral stationary phase at different temperatures and at different mobile phase compositions, using the reversed-phase mode. With variation of both mobile phase composition and temperature, almost baseline separations could be achieved for all four enantiomers of sterically hindered amino acids. The retention factors and selectivity factors for the enantiomers of all investigated compounds decreased with increasing temperature. The natural logarithms of the retention factors (ln k) of the investigated compounds depended linearly on the inverse of temperature (1/T). van 't …

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Network Modeling Of The Intraparticle Convection And Diffusion Of Molecules In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis Dec 1998

Network Modeling Of The Intraparticle Convection And Diffusion Of Molecules In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A pore network model (cubic lattice network) is constructed to represent the porous structure in a column packed with porous chromatographic particles. Expressions are developed and used to determine, through the utilization of the pore network model, the intraparticle interstitial fluid velocity and pore diffusivity of a solute as the pore connectivity, n(T), of the porous medium is varied from 2.6 to 6.0. The results show that the intraparticle interstitial velocity and the pore diffusivity increase significantly as the value of the pore connectivity, n(T), increases, and clearly indicate that the pore connectivity, n(T), plays a key role in determining …

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The Missouri Miner, December 09, 1998 Dec 1998

The Missouri Miner, December 09, 1998

The Missouri Miner Newspaper

No abstract provided.

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The Missouri Miner, December 02, 1998 Dec 1998

The Missouri Miner, December 02, 1998

The Missouri Miner Newspaper

No abstract provided.

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Differences Between Regular And Random Order Of Updates In Damage-Spreading Simulations, Thomas Vojta, Michael Schreiber Dec 1998

Differences Between Regular And Random Order Of Updates In Damage-Spreading Simulations, Thomas Vojta, Michael Schreiber

Physics Faculty Research & Creative Works

We investigate the spreading of damage in the three-dimensional Ising model by means of large-scale Monte Carlo simulations. Within the Glauber dynamics we use different rules for the order in which the sites are updated. We find that the stationary damage values and the spreading temperature are different for different update order. In particular, random update order leads to larger damage and a lower spreading temperature than regular order. Consequently, damage spreading in the Ising model is nonuniversal not only with respect to different update algorithms (e.g., Glauber vs heat-bath dynamics) as already known, but even with respect to the …

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Production Of Bound Μ⁺Μˉ Systems In Relativistic Heavy Ion Collisions, Ilya F. Ginzburg, Ulrich D. Jentschura, Savely Karshenboim, Frank Krauss, Valery G. Serbo, Gerhard Soff Dec 1998

Production Of Bound Μ⁺Μˉ Systems In Relativistic Heavy Ion Collisions, Ilya F. Ginzburg, Ulrich D. Jentschura, Savely Karshenboim, Frank Krauss, Valery G. Serbo, Gerhard Soff

Physics Faculty Research & Creative Works

Dimuonium (the bound system of two muons, the μ+ μ--atom system) has not been observed yet. In this paper we discuss the electromagnetic production of dimuonium at RHIC and LHC in relativistic heavy ion collisions. The production of parastates is analyzed in the equivalent photon approximation. For the treatment of orthostates, we develop a three-photon formalism. We determine the production rates at RHIC and LHC with an accuracy of a few percent and discuss problems related to the observation of dimuonium.

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An Image Model Based On Occluding Object Images And Maximum Entropy, John A. Stuller, Rahul Shah Dec 1998

An Image Model Based On Occluding Object Images And Maximum Entropy, John A. Stuller, Rahul Shah

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Introduces a Statistical Image Model based on Occlusion and Maximum Entropy. the Statistical Model Combines a Fundamental Property of Image Formation, Occlusion, with Both Object-Image Shape and Nonuniform Object-Image Intensity. the Model is a Composition of Individual Object-Images that Have Random Positions, Shapes, and Intensities, and that Occlude Both Background and One Another. We Derive the Autocorrelation and Second-Order Probability Density Functions of This Model and Give Several Examples. © 1998 IEEE.

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Study On The Estimation And Control Of A Liquid Composite Molding Process, Dennis Sourlas, Susmito Naha, Gary Patterson, Richard Parnas Dec 1998

Study On The Estimation And Control Of A Liquid Composite Molding Process, Dennis Sourlas, Susmito Naha, Gary Patterson, Richard Parnas

Chemical and Biochemical Engineering Faculty Research & Creative Works

An on-line nonlinear receding horizon control algortithm is employed in order to achieve setpoint tracking targets in the context of liquid composite molding processes. The robustness of this control strategy against process-model deviations is tested. Finally, recursive parameter estimation is employed as a means of actively enhancing the performance of the process control algorithm. © 1998 AACC.

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Powergraf: An Educational Software Package For Power Systems Analysis And Design, Tian Yane, Max Darwin Anderson Dec 1998

Powergraf: An Educational Software Package For Power Systems Analysis And Design, Tian Yane, Max Darwin Anderson

Electrical and Computer Engineering Faculty Research & Creative Works

The purpose of PowerGraf is to present a graphical user interface (GUI) and a convenient tool for building one-line diagrams displaying data. The GUI is open and friendly for power systems design, analysis and control, because a picture provides a better illustration of cause-and-effect relationships than a tabular printout does. Basic elements such as buses, lines and transformers are given such that the power system topology is easily drawn with this tool, and the system parameters are entered on the picture and checked visually. This enables the power system topology and the system data to be shown on one picture …

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Charge Exchange From D(N = 2) Atoms To Low-Z Receiver Ions, R. Hoekstra, H. Anderson, F. W. Bliek, M. Von Hellermann, C. F. Maggi, Ronald E. Olson, H. P. Summers Dec 1998

Charge Exchange From D(N = 2) Atoms To Low-Z Receiver Ions, R. Hoekstra, H. Anderson, F. W. Bliek, M. Von Hellermann, C. F. Maggi, Ronald E. Olson, H. P. Summers

Physics Faculty Research & Creative Works

To elucidate the influence on charge-exchange spectroscopy of metastable deuterium donors, the corresponding cross sections for state-selective charge transfer have been calculated using the classical trajectory Monte Carlo method. The cross sections for electron capture from D(n = 2) by fully stripped low-Z ions are contrasted with those for capture from ground state D to indicate the importance of metastable donors. Using the new data, effective emission coefficients for the spectral lines of H-like light impurities used in charge-exchange spectroscopy have been calculated. These results incorporate the presence of excited n = 2 donors in the beam and apply to …

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Nonanalytic Magnetization Dependence Of The Magnon Effective Mass In Itinerant Quantum Ferromagnets, Dietrich Belitz, Theodore R. Kirkpatrick, Andrew J. Millis, Thomas Vojta Dec 1998

Nonanalytic Magnetization Dependence Of The Magnon Effective Mass In Itinerant Quantum Ferromagnets, Dietrich Belitz, Theodore R. Kirkpatrick, Andrew J. Millis, Thomas Vojta

Physics Faculty Research & Creative Works

The spin-wave dispersion relation in both clean and disordered itinerant quantum ferromagnets is calculated. It is found that effects akin to weak-localization physics cause the frequency of the spin waves to be a nonanalytic function of the magnetization m. For low frequencies Ω, small wave vectors k, and m→0, the dispersion relation is found to be of the form Ω=const x m1-αk2, with α = (4-d)/2 (2 < d < 4) for disordered systems, and α = (3-d) (1 < d < 3) for clean ones. In d = 4 (disordered) and d = 3 (clean), Ωαm ln (1/m) k2. Experiments to test these predictions are proposed.

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Determination Of The Tensile And Shear Strengths Of Screws And The Effect Of Screw Patterns On Cold-Formed Steel Connections, Marc Allen Sokol, Roger A. Laboube, Wei-Wen Yu Dec 1998

Determination Of The Tensile And Shear Strengths Of Screws And The Effect Of Screw Patterns On Cold-Formed Steel Connections, Marc Allen Sokol, Roger A. Laboube, Wei-Wen Yu

CCFSS Library (1939 - present)

PREFACE This report summarizes two studies related to the design of cold-formed steel connections. The study topics included the creation of a test standard for determining the strength of a screw, and the determination of the strength of a screw connection. A standard test protocol does not exist for determining the strength of a screw. Today, manufacturers use test protocols developed for their products. Thus, there is no consistency in defining the structural performance of a screw. A test standard has been developed. The standard used as its model the American Society of Testing and Material's F 606, Standard Test …

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Double Differential Cross Section Of Helium Ionization By Proton Impact, A. L. Godunov, V. A. Schipakov, Michael Schulz Nov 1998

Double Differential Cross Section Of Helium Ionization By Proton Impact, A. L. Godunov, V. A. Schipakov, Michael Schulz

Physics Faculty Research & Creative Works

A theoretical analysis for doubly differential cross sections of the single ionization of helium by proton impact as a function of the scattering angle and projectile energy loss is presented. We have used two different theoretical methods. The first approach involved an approximate solution of Faddeev-Merkuriev equations for the three-body Coulomb problem. The second approach employed the expansion of the transition amplitude in the Born series over the projectile-target interaction up to second order. A relation between these two methods was established for the case of fast collisions. It has been demonstrated that, for small scattering angles, the post-collision interaction …

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Vacancy Clustering In Quenched Al-Li Solid Solution Alloys Studied By Doppler Broadening Spectroscopy, Hollis P. Leighly, P. G. Coleman Nov 1998

Vacancy Clustering In Quenched Al-Li Solid Solution Alloys Studied By Doppler Broadening Spectroscopy, Hollis P. Leighly, P. G. Coleman

Materials Science and Engineering Faculty Research & Creative Works

The clustering of vacancies in severely quenched Al-Li solid solution alloys, with Li content between 230 and 2760 ppm, has been studied using Doppler broadening spectroscopy. The alloy samples were initially annealed at 873 K in dry air or dry, pure nitrogen. The onset temperature for vacancy clustering in samples initially annealed in air was found to be 150 ± 10 K, 40 ± 15 K lower than for the nitrogen-annealed samples. This result is consistent with the migration of divacancies, formed as a result of the significant increase in vacancy concentration caused by Li migration to, and oxidation at, …

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The Missouri Miner, November 18, 1998 Nov 1998

The Missouri Miner, November 18, 1998

The Missouri Miner Newspaper

No abstract provided.

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Ultralow-Energy Electrons From Fast Heavy-Ion Helium Collisions: The “Target Cusp“, W. Schmitt, R. Moshammer, F. S.C. O'Rourke, H. Kollmus, L. Sarkadi, R. Mann, S. Hagmann, Ronald E. Olson, J. Ullrich Nov 1998

Ultralow-Energy Electrons From Fast Heavy-Ion Helium Collisions: The “Target Cusp“, W. Schmitt, R. Moshammer, F. S.C. O'Rourke, H. Kollmus, L. Sarkadi, R. Mann, S. Hagmann, Ronald E. Olson, J. Ullrich

Physics Faculty Research & Creative Works

Doubly differential cross sections d2σ / dν ‖ dν⊥ have been obtained by mapping the 3-dimensional velocity space of ultralow- and low-energy electrons \ (1.5 meV < = Ee < = 100 eV \) emitted in singly ionizing 3.6 MeV / u Au53+ on helium collisions. A sharp \ ( ΔEFWHMe⊥< = 22 meV \) asymmetric peak centered at = 0 is observed to emerge at ultralow energies from the strongly forward shifted low-energy electron velocity distribution. The shape of this "target cusp," which is very sensitive on the details of the two-center potential, is in excellent accord with theoretical predictions. © 1998 The American Physical Society.

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The Missouri Miner, November 11, 1998 Nov 1998

The Missouri Miner, November 11, 1998

The Missouri Miner Newspaper

No abstract provided.

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Specific Heat And Transport “Anomalies” In Mixed Alkali Glasses, Peter F. Green, Richard K. Brow, James J. Hudgens Nov 1998

Specific Heat And Transport “Anomalies” In Mixed Alkali Glasses, Peter F. Green, Richard K. Brow, James J. Hudgens

Materials Science and Engineering Faculty Research & Creative Works

We show that changes in the relative mole fractions of Li2O and Na2O in alkali metaphosphate glasses lead to “anomalies” in the specific heat and structural relaxations. The heat capacity change between the liquid and glassy states, Δcp(Tg), at the calorimetric glass transition temperature, Tg, exhibits a minimum when the mole fractions of Li2O and Na2O are comparable. Moreover, systematic changes in the temperature dependence of the viscosity, η, i.e., changes in the “fragility” of the system, accompany these changes in mole fraction. This observed dependence …

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The Missouri Miner, November 04, 1998 Nov 1998

The Missouri Miner, November 04, 1998

The Missouri Miner Newspaper

No abstract provided.

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A Virtual Classroom Via Dataconferencing: A Multi-Institutional Experience, Shelli K. Starrett, Anil Pahwa, Kraig J. Olejniczak, S. D. Sudhoff, Mariesa Crow Nov 1998

A Virtual Classroom Via Dataconferencing: A Multi-Institutional Experience, Shelli K. Starrett, Anil Pahwa, Kraig J. Olejniczak, S. D. Sudhoff, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the experience of five faculty from four universities who are co-developing and team teaching courses using the world-wide web (WWW). In particular two novel power engineering courses, Flexible Control of Transmission Systems and Flexible Control of Distribuction Systems, introduce the student to the application of power electronic-based controllers, known specifically as flexible AC transmission systems (FACTS) controllers, to enhance the performance of the transmission and distribution systems in an electric power system. In order to leverage faculty expertise in the various topics included in each course, a unique partnership was formed among five faculty from the following …

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Predictive Relationships For Uptake Of Organic Contaminants By Hybrid Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor Nov 1998

Predictive Relationships For Uptake Of Organic Contaminants By Hybrid Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Twelve Organic Compounds Commonly Found at Hazardous Waste Sites Were Studied for Uptake by Hybrid Poplar Trees. the Vegetative Uptake of Many of These Compounds Has Not Previously Been Demonstrated for Plant Species Being Utilized for Phytoremediation, Such as Hybrid Poplar Trees. Experiments Were Conducted Hydroponically Utilizing 14C-Labeled Compounds to Ascertain Translocation and Fate. Predictive Relationships for the Translocation and Partitioning to Plant Tissues Were Developed from the Experimental Data. Translocation and Partitioning Relationships based on Compounds' Octanol- Water Partitioning Coefficients (100 K(Ow)) Produced the Best Results, But the Relationships Did Not Allow for Fully Accurate Prediction of Each Contaminant's …

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Productivity Improvement At A High-Tech State-Owned Industry--An Indonesian Case Study Of Employee Motivation, Adik A. Soedarsono, Susan L. Murray, Yildirim Omurtag Nov 1998

Productivity Improvement At A High-Tech State-Owned Industry--An Indonesian Case Study Of Employee Motivation, Adik A. Soedarsono, Susan L. Murray, Yildirim Omurtag

Engineering Management and Systems Engineering Faculty Research & Creative Works

The purpose of this case study was to identify the level of employee motivation at an Indonesian high-tech state-owned company. Comparisons were drawn between labor and management as well as Indonesian and Western industrial environments. The overall results provide insight into employee motivation and the potential for productivity improvement that should prove beneficial to management at state-owned and privately owned companies in Indonesia and the Pacific Rim. The study can also help Westerners appreciate culture differences and productivity challenges in this developing country.

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Essential Role Of Correlations In Governing Charge Transport In Disordered Organic Materials, Sergei V. Novikov, David H. Dunlap, Vasudev M. Kenkre, Paul Ernest Parris, Anatoly V. Vannikov Nov 1998

Essential Role Of Correlations In Governing Charge Transport In Disordered Organic Materials, Sergei V. Novikov, David H. Dunlap, Vasudev M. Kenkre, Paul Ernest Parris, Anatoly V. Vannikov

Physics Faculty Research & Creative Works

The transport of photoinjected charges in disordered organic films is often interpreted using a formula based on a Gaussian disorder model (GDM) that neglects spatial correlations due to charge-dipole interactions, even though such correlations have recently been shown to explain the universal electric field dependence observed in these systems. Based on extensive computer simulations of a 3D disorder model that includes such correlations, we present a new formula for analyzing experiments that accurately describes transport in these materials.

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Do Interactions Increase Or Reduce The Conductance Of Disordered Electrons? It Depends!, Thomas Vojta, Frank Epperlein, Michael Schreiber Nov 1998

Do Interactions Increase Or Reduce The Conductance Of Disordered Electrons? It Depends!, Thomas Vojta, Frank Epperlein, Michael Schreiber

Physics Faculty Research & Creative Works

We investigate the influence of electron-electron interactions on the conductance of two-dimensional disordered spinless electrons. We present an efficient numerical method based on diagonalization in a truncated basis of Hartree-Fock states to determine with high accuracy the low-energy properties in the entire parameter space. We find that weak interactions increase the dc conductance in the strongly localized regime while they decrease the dc conductance for weak disorder. Strong interactions always decrease the conductance. We also study the localization of single-particle excitations at the Fermi energy which turns out to be only weakly influenced by the interactions.

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Comparison Of Electron-Atom Collision Parameters For S To P Transitions Under Reversal Of Energy Transfer, Max Shurgalin, Andrew James Murray, William R. Macgillivray, M. C. Standage, Don H. Madison, Kathrin D. Winkler, Igor Bray Nov 1998

Comparison Of Electron-Atom Collision Parameters For S To P Transitions Under Reversal Of Energy Transfer, Max Shurgalin, Andrew James Murray, William R. Macgillivray, M. C. Standage, Don H. Madison, Kathrin D. Winkler, Igor Bray

Physics Faculty Research & Creative Works

Inelastic and superelastic electron scattering from the optically prepared 32P3/2 state of sodium has enabled atomic collision parameters to be deduced for the 4S-3P deexcitation and the 3S-3P excitation processes. These data are compared with convergent close coupling and second order distorted wave Born calculations. For excitation, both theories agree with experiment, whereas for deexcitation the close coupling theory is in better agreement. A long-standing proposal relating to the sign of the transferred angular momentum is not supported.

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The Missouri Miner, October 28, 1998 Oct 1998

The Missouri Miner, October 28, 1998

The Missouri Miner Newspaper

No abstract provided.

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The Missouri Miner, October 21, 1998 Oct 1998

The Missouri Miner, October 21, 1998

The Missouri Miner Newspaper

No abstract provided.

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Distortional Buckling Formulae For Thin Walled Channel And Z-Sections With Return Lips, John T. Merrick, Gregory J. Hancock, M. R. Bamach Oct 1998

Distortional Buckling Formulae For Thin Walled Channel And Z-Sections With Return Lips, John T. Merrick, Gregory J. Hancock, M. R. Bamach

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Cold-formed Channel- and Z-sections subject to both flexure and torsion may undergo distortional buckling where the flange and lip rotate about the flange/web junction. This mode of failure is prevalent in purlin sections when lateral deformation of the section is prevented and when the sections are manufactured from high strength steel. In an attempt to prevent distortional buckling, some manufacturers have added additional return lips to the flange lips to produce complex edge stiffeners. The Australian/New Zealand Standard for Cold-Formed Steel Structures includes design rules for determining the distortional buckling strength of cold-formed beam and column sections. These design rules …

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Behaviour Of Thin G550 Sheet Steel Bolted Connections, Colin A. Rogers, Gregory J. Hancock Oct 1998

Behaviour Of Thin G550 Sheet Steel Bolted Connections, Colin A. Rogers, Gregory J. Hancock

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper provides a summary of results detailing the behaviour of bolted connections tested in shear, which were composed of 0.42 mm G550, 0.60 mm G550 and 0.60 mm G300 sheet steels (to the 1993 Australian Standard AS 1397). Recommendations concerning the adequacy of current design standards with respect to the design of thin sheet steel bolted connections are made, along with the calibration of applicable limit states resistance equations for the three observed modes of failure; end pull-out, bearing, and net section fracture.

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